1: (4-fluoro-phenyl)-carbamic acid tert-butyl ester With tert.-butyl lithium in tetrahydrofuran; pentane T=-50°C; 3 h; 2: N,N-dimethyl-formamide in tetrahydrofuran; pentane T=-50 - 25°C;

1.1: 84 percent / toluene / 2 h / Heating 2.1: tert-butyllithium / tetrahydrofuran; pentane / 3 h / -50 °C 2.2: 71 percent / tetrahydrofuran; pentane / -50 - 25 °C View Scheme

1.1: 84 percent / toluene / 2 h / Heating 2.1: tert-butyllithium / tetrahydrofuran; pentane / 3 h / -50 °C 2.2: 71 percent / tetrahydrofuran; pentane / -50 - 25 °C View Scheme

1.1: tert-butyllithium / tetrahydrofuran; pentane / 0.25 h / -25 °C 1.2: 66 percent / tetrahydrofuran; pentane 2.1: 46 percent / potassium tert-butoxide / 2-methyl-propan-2-ol / 5 h / 80 °C View Scheme

1.1: tert-butyllithium / tetrahydrofuran; pentane / 0.25 h / -25 °C 1.2: 66 percent / tetrahydrofuran; pentane 2.1: 46 percent / potassium tert-butoxide / 2-methyl-propan-2-ol / 5 h / 80 °C 3.1: 93 percent / BuLi / hexane; tetrahydrofuran / 25 °C 4.1: 2,2,6,6-tetramethylpiperidine; N,N,N',N'-pentamethyldiethylenetriamine; BuLi / tetrahydrofuran; hexane / 6 h / -75 °C 4.2: 62 percent / 1,1,2-trichloro-1,2,2-trifluoroethane / tetrahydrofuran; hexane / -75 - 25 °C 5.1: 94 percent / tetrabutylammonium fluoride hydrate / tetrahydrofuran / 25 °C View Scheme